Biology

Human Genetics and Disorders

844 Questions

Human Genetics and Disorders covers the inheritance patterns, genetic mutations, and molecular basis of hereditary diseases. Topics include sex-linked traits, cancer genetics, and metabolic disorders. This section tests knowledge critical for biology exams and general science papers.

Genetic mutationsInherited disordersCancer geneticsGenetic testingMendelian inheritance

Human Genetics and Disorders Questions

Multiple choice biology blood circulatory system of human cardiac disorders cardiac regulation and disorders the blood system

The incorrect statement with regard to haemophilia is

  1. It is a recessive disease.

  2. It is a dominant disease.

  3. A single protein involved in the clotting in blood is affected.

  4. It is sex-linked disease.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Haemophilia is a group of hereditary genetic disorders that impair the body's ability to control blood clotting, which is used to stop bleeding when a blood vessel is broken.
It is recessive (not dominant) sex-linked, X-chromosome disorder.
Thus, the correct answer is option (B), 'It is a dominant disease'.

Multiple choice biology blood circulatory system of human cardiac disorders cardiac regulation and disorders the blood system

The disease erythroblastosis fetalis in human embryo is caused due to:

  1. Disadjustment of blood groups

  2. Disadjustment of Rh factor

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Erythroblastosis fetalis is hemolytic anemia in the fetus caused by transplacental transmission of maternal antibodies to the fetal RBCs. The disorder usually results from incompatibility between the maternal and fetal blood groups, often Rh antigens. Erythroblastosis fetalis classically results from Rh incompatibility, which may develop when a woman with Rh-negative blood is impregnated by a man with Rh-positive blood and conceives a fetus with Rh-positive blood.
Thus, the correct answer is option (B), 'Disadjustment of Rh factor'.

Multiple choice zoology immunity and blood groups compatibility of blood groups blood group blood groups and compatibility advance

Biological marriage of one of the following should be avoided
                                                 or

After examining the blood groups of a couple, the doctor advised them not to have more than one child. The blood group of the couple are likely to be

                                                or

In which of the following situations, is there a risk factor for children of incurring erythroblastosis foetalis

  1. Rh+ male and Rh- female

  2. Rh+ male and Rh+ female

  3. Rh- male and Rh+ female

  4. Rh- male and Rh- female
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Erythroblastosis foetalis occurs when an Rh-negative mother carries an Rh-positive fetus, leading to the production of anti-Rh antibodies.

Multiple choice zoology immunity and blood groups compatibility of blood groups blood group blood groups and compatibility advance

Name of the disease due to Rh factor.

  1. Accquired Immuno Deficiency Syndrome

  2. Turner's Syndrome

  3. Erythroblastosis foetalis

  4. Sickle - cell anaemia
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When a woman is pregnant having Rh negative blood group and the blood group of the foetus is Rh positive, then her baby's blood type will be incompatible with her own. This can cause a condition known as erythroblastosis fetalis, where the mother's red blood cells attack those of the baby as there would any foreign invaders. Rh incompatibility and ABO incompatibility are the two main cause. Both are associated with blood type. Thus, the correct answer is option C.

Multiple choice evs - i busy at work - our internal organs human lymphatic system lymph and its function lymph and tissue fluid

If the father has blood group A and mother has blood group O, which one of following may be the son's blood group?

  1. B

  2. AB

  3. O

  4. B, AB and O
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If the father is blood group A (genotype AA or AO) and the mother is O (genotype OO), the possible offspring genotypes are AO or OO, resulting in blood group A or O.

Multiple choice zoology body fluids and circulation compatibility of blood groups blood group blood groups and compatibility advance

Rh factor may be responsible for

  1. Turner's syndrome

  2. Accquired Immuno Deficiency Syndrome

  3. Sickle cell anaemia

  4. Erythroblastosis foetalis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Erythroblastosis foetalis is a disease of the new born which is caused by Rh incompatibilty. This happens when mother is Rh negative and the child she is bearing is Rh positive. Thus the Rh antigen of child can trigger the antibodies inside mother which can travel through circulation thus destroying foetus blood cells. Thus, correct answer is option D.

Multiple choice biology the age of adolescence menstruation in females changes at puberty what happens if an egg is not fertilized?

The cause of Cat-cry syndrome is due to

  1. Loss of a segment of X-chromosome

  2. Loss of a segment of 5"' chromosome

  3. Loss of segment of Y-chromosome

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cat-cry or cri-due chat syndrome is caused by the deletion of short arm of chromosome number 5 (5p). So, the genotype of affected individual in 46, XX, Sp- in female and 46, XX, 5p in males.

Multiple choice evs science of kitchen balanced diet and malnutrition assimilation of food components and importance of food skeletal system and muscles assimilation of food and egestion busy at work - our internal organs

Haemolytic jaundice is caused by a dominant gene but only 10% of the people actually develop it. What proportion of the children would be expected to develop the disease, if a heterozygous man marries a homozygous normal woman?

  1. 1/5

  2. 1/10

  3. 1/15

  4. 1/20
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Genotype of the man --> A$^H$A (where A$^H$ is the chromosome carrying dominant gene for haemolytic jaundice and A is the homologous chromosome carrying the normal allele).
Genotype of woman --> AA
P generation :          A$^H$A    X     AA


F$ _1$ generation :     A$^H$A   A$^H$A   AA    AA
                          (Diseased:Normal) = (1:1)
Only 10% of the people having diseased genotype actually suffer from haemolytic jaundice, this turns the ratio to (0.1:1).
Thus, proportion of children expected to develop the disease for the given cross= 0.1/2 (0.1 children are affected out of two children) = 1/20

Multiple choice evs we are special defects of eye disorders of nervous system braille script

Which of the following disorder is not hereditary?

  1. Haemophilia

  2. Cataract

  3. Sickle cell anaemia

  4. Colour blindness
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A. Haemophilia is a X-linked recessive genetic disorder that occurs due to deficiency of clotting factors in the blood and therefore, there is no formation of clot at the site of wound. 
B. Cataract is an eye disease that occurs in older people. The visibility is reduced because the eye lens becomes opaque. It is treated by surgery.
C. Sickle cell anaemia is a autosomal recessive genetic disorder in which red blood cells become sickle shaped and this causes oxygen tension in the body.
D. Colour blindness is a X-linked genetic disorder in which there is inability to distinguish colours due to defect in cones (photoreceptor cells associated with daylight vision and colour vision).
Hence, cataract is not hereditary because it is not a genetic disorder.
So, the correct answer is 'Cataract'.
Multiple choice evs we are special defects of eye disorders of nervous system braille script

Which one of the following diseases in man belongs to the same category as haemophilia?

  1. Hypermetropia

  2. Rabies

  3. Night blindness

  4. Colour blindness
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Colour blindness and haemophilia are both X-linked recessive disorders. 

Red-green colour blindness, a very common trait in humans affects between 7% and 10% of men and 0.49% to 1% of women. 
Hemophilia A, a blood clotting disorder is caused by a mutation of the factor VIII gene and hemophilia B, also known as 'Christmas disease', is a blood clotting disorder, caused by a mutation of the factor IX gene. 

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Haemophilia is a condition where there is 

  1. A failure in the clotting mechanism of blood

  2. A delay in the clotting of blood

  3. No production of haemoglobin in the blood

  4. No production of melanin in the skin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Haemophilia is a group of hereditary genetic disorders in which the body's blood clotting ability fails to stop bleeding if any cut happens.
  • Thus, it is also known as bleeder's disease. One type of haemophilia called haemophilia A happens due to the deficiency of blood clotting factor VIII. 
Therefore, the correct answer is option A.

Multiple choice

Hemophilia is a sex-linked trait.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hemophilia is a classic example of an X-linked recessive trait, meaning the gene responsible is located on the X chromosome.

Multiple choice

Can sickle cell anemia be passed down if only one parent possesses the gene?

  1. Yes

  2. No

  3. It depends on the gender of the parent and offspring
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sickle cell anemia is an autosomal recessive disorder. A person must inherit two copies of the mutated gene (one from each parent) to have the disease; if only one parent possesses the gene, the offspring can be a carrier but will not have the disease.